The purpose of the study is to examine the effects of switching from antiretroviral
combinations that includes efavirenz (Sustiva®), lopinavir/ritonavir (Kaletra®) or
atazanavir/ritonavir (Reyataz®/Norvir®) in individuals experiencing side effects from one of
these agents, and replacing these with a new HIV medication called Darunavir also given with
ritonavir (Norvir®).
The study will primarily investigate the effect of change in medication on the subjects viral
load (the levels of the HIV virus in the blood), on immunological parameters (CD4 count) and
on other safety parameters (such as cholesterol) and also quality of life.